RT Journal Article SR Electronic T1 Correlation Between Interferon Alpha Receptor Protein Expression and Sensitivity to Interferon Alpha Subtypes in Human Renal Carcinoma Cell Lines JF Cancer Genomics - Proteomics JO Cancer Genomics Proteomics FD International Institute of Anticancer Research SP 87 OP 94 VO 1 IS 1 A1 TOSHIO ARIYASU A1 NOBORU FUJIOKA A1 SHIGETO YAMAMOTO A1 YOSHIAKI YANAI A1 HIROSHI YAMAUCHI A1 HAKUO IKEGAMI A1 MASAO IKEDA A1 MASASHI KURIMOTO A1 SHIGEO HORIE A1 TADAICHI KITAMURA YR 2004 UL http://cgp.iiarjournals.org/content/1/1/87.abstract AB Background: We have previously characterized the antitumor activities and immunological properties of interferon-alpha (IFN-α) subtypes on renal cell carcinoma (RCC). However, the mechanism responsible for the different biologic activities among the IFN-α subtypes is still unclear. To explain the different cellular sensitivities to IFN-α subtypes, detailed expression of the interferon-alpha receptor (IFNAR)-1 and IFNAR-2 subunits on different RCC cell lines was examined and compared with sensitivity of the cell lines to the IFN-α subtypes. Materials and Methods: We investigated the antiproliferative effects of natural IFN-α subtypes (IFN-α2 and IFN-α8) using eight RCC cell lines. IFNAR-1 and IFNAR-2 expression were determined by RT-PCR and Western blotting. To determine a possible relationship between IFN activity and IFNAR expression, the correlation between the 50% effective IFN dose (ED50) for growth inhibition and the level of IFNAR expression was statistically examined. Results: We report here that IFN-α8 more potently induced growth inhibition than IFN-α2 in the majority of the RCC cell lines examined, this being in accordance with our previous results. The ED50 value of IFN-α8 was lower than 1000 (IU/ml) in six of the eight cell lines, whereas that of IFN-α2 was lower than 1000 (IU/ml) in three of the eight cell lines. The results of experiments using Western blotting analysis revealed that IFN-α subtype sensitivities were closely correlated with the expression level of IFNAR-2(c), a long form of the IFNAR-2 protein, in seven of the eight cell lines. Conclusion: These results suggest that the intensity of IFNAR-2(c) protein expression could be an important prognostic marker for clinical application of particular IFN-α subtypes in RCC.